Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
539 FXUS62 KCHS 251829 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 129 PM EST Tue Nov 25 2025 .SYNOPSIS... High pressure will prevail through today, then a strong cold front will sweep through late Wednesday. High pressure will usher in colder weather Thursday through the weekend. && .NEAR TERM /THROUGH TONIGHT/... High pressure centered offshore of the Mid-Atlantic will dampen a mid-lvl trough as it continues to eject out of the Mid- Mississippi Valley into the Appalachians. An associated cold front will traverse southeastward across the Deep South tonight, and expected to pass through the region late Wednesday evening. Ahead of this boundary, a weak coastal trough has been meandering offshore of the South Carolina coastline over the past couple hours. This feature has yielded light to moderate rain showers across the Charleston Tri-County, and recent rainfall amounts indicate 0.05 to 0.15 inches have fallen over the last 2-3 hours. This system should washout in the afternoon as southerly flow increases along the backside of the high pressure located to the northeast of the region and the isentropic lift decreases with the exit of the trough. Temperatures across the Charleston Tri-County might be limited as clouds and precipitation have hindered it`s ability to warm- up throughout the morning. Outside of the Tri- County, afternoon temperatures will reach into the low to mid 70s across the SE South Carolina and upper 70s to low 80s across SE Georgia. Tonight: Expect warm, southerly slow to persist overnight as the aforementioned cold front approaches the region and a pronounced pre- frontal low-lvl jet intensifies across the Southeastern CONUS. With plenty of moisture remaining across the region, it`s possible to see some pre-frontal showers across the interior counties a couple hours before sunrise. This will keep the boundary layer well-mixed with lows in the 58-62 range inland with lower 60s at the beaches. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... Wednesday: As longwave troughing dominates aloft, a strong cold front will pass through the region late this evening. Expect to see a couple isolated showers in the morning across the interior counties as a considerable amount of moisture remains with PWATs ranging from 1.5 to 1.75 inches. However, dry-air is expected to take-over in the afternoon and rain chances will significantly decrease across the coastal counties ahead of the boundary. Also, with the lack of dynamics present, it`ll be difficult to see much rainfall (esp. near the coastline). It`s important to note that southwesterly winds will become quite gusty out ahead of the front, and the forecast is likely underdone in this category. Temperatures will reach into the mid to upper 70s, before dropping out overnight behind the passage of the cold front with lows dipping into the upper 30s to low 40s across the interior counties and mid to low 50s at the beaches. Thursday and Friday: Expect cold, dry conditions to persist into Friday as high pressure builds into the region behind the frontal passage. Aloft, zonal flow will takeover and maintain quiet conditions across the Southeastern CONUS. A rain-free forecast has been maintained until the end of this period. However, temperatures will be noticeably cooler, with highs in the upper 50s to low 60s on Thursday and the low to mid 50s on Friday. Overnight lows will dip into the 30s across most locations Thursday night, with freezing temperatures likely across the far interior. However, the local frost/freeze program ended earlier this month with the widespread freeze, so no Freeze headlines will be issued. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... Dry, cool conditions will persist throughout the weekend as zonal flow dominates the pattern aloft and high pressure remaining situated at the surface. Therefore, a rain-free forecast has been maintained with temperatures below normal. There has been some indication of a coastal low forming and impacting the region early next week in some of the deterministic guidance. However, a good amount of uncertainty remains on timing and arrival of this system. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... 25/18z TAF Discussion: KCHS/KJZI/KSAV: As a coastal trough lifts up the coast early this afternoon, a short period of flight restrictions will occur at KCHS and KJZI before returning to VFR by 19Z. There should be enough low- level flow overnight to prevent the development of fog despite a fairly moist airmass. SSW winds could get a little gusty at KCHS Wednesday afternoon as the cold front approaches. Extended Aviation Outlook: Prevailing VFR. && .MARINE... Through Tonight: As the weak coastal trough across the local waters wanes this afternoon, expect the on-going rain showers taper off. With the low-lvl jet intensifying and the cold front approaching from the Deep South, southerly flow will increase to 10 to 15 kts with gusts up to 20 kts possible. Seas will average 2 to 3 ft in the nearshore wasters and 3 to 4 ft offshore waters. Wednesday through Friday: A cold front is forecast to push through the region late Wednesday evening. Southwesterly winds will surge ahead of the approaching front on Wednesday. It`s possible to see wind speeds of 15 to 20 kts with some gusts to 22-23 kts possible (mainly in the Charleston nearshore waters). Post-FROPA conditions will yield a wind shift to the northeast as high pressure builds into the marine waters with speeds of 10 to 15 kts and gusts up to 20 kts. Small Craft Advisories will not be issued at this time as conditions remain below the criteria. Seas will range from 2 to 3 ft with 4 footers possible in the 20 to 60 nm offshore GA waters. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...Dennis SHORT TERM...Dennis LONG TERM...Dennis AVIATION...Dennis/JRL MARINE...Dennis